109P/Swift-Tuttle
| Parameter |
Value |
| Designation |
109P/Swift-Tuttle |
| Type |
P |
| Perihelion (tp_cal, UTC) |
1992-12-11T23:59:41.389440Z |
| Orbit solution date (soln_date, UTC) |
2001-10-09T15:34:49Z |
| Obs used |
652 |
| NEO |
Yes |
| M1 |
4.500 |
| K1 |
15.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1995-10-10.0000000 |
| e |
0.96322576 |
| q (au) |
0.959516 |
| a (au) |
26.092069 |
| i (deg) |
113.453817 |
| Ω (om, deg) |
139.381192 |
| ω (w, deg) |
152.982168 |
| M (ma, deg) |
7.631696 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.041 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.041 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.996 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 1992-01-03 |
1992-09-28 |
+4.8769 |
-0.085 |
| 1992-09-28 |
1992-12-11 |
+4.4161 |
-0.144 |
| 1992-12-12 |
1994-10-07 |
+3.1486 |
-0.149 |
| 1994-10-07 |
2023-11-20 |
-26.6968 |
+25.479 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
09:40:40.62 |
-19:45:05.3 |
HIP 47552 |
16.48 |
| 2026-02-03 12:00 |
09:40:37.78 |
-19:44:56.2 |
HIP 47429 |
16.52 |
| 2026-02-04 00:00 |
09:40:34.92 |
-19:44:46.9 |
HIP 47429 |
15.94 |
| 2026-02-04 12:00 |
09:40:32.07 |
-19:44:37.4 |
HIP 47429 |
15.37 |
| 2026-02-05 00:00 |
09:40:29.21 |
-19:44:27.6 |
HIP 47429 |
14.80 |
| 2026-02-05 12:00 |
09:40:26.35 |
-19:44:17.6 |
HIP 47429 |
14.24 |
| 2026-02-06 00:00 |
09:40:23.48 |
-19:44:07.4 |
HIP 47429 |
13.69 |
| 2026-02-06 12:00 |
09:40:20.61 |
-19:43:57.0 |
HIP 47429 |
13.15 |
| 2026-02-07 00:00 |
09:40:17.74 |
-19:43:46.3 |
HIP 47429 |
12.62 |
| 2026-02-07 12:00 |
09:40:14.87 |
-19:43:35.5 |
HIP 47429 |
12.10 |
| 2026-02-08 00:00 |
09:40:11.99 |
-19:43:24.4 |
HIP 47429 |
11.60 |
| 2026-02-08 12:00 |
09:40:09.12 |
-19:43:13.1 |
HIP 47429 |
11.12 |
| 2026-02-09 00:00 |
09:40:06.24 |
-19:43:01.5 |
HIP 47429 |
10.66 |
| 2026-02-09 12:00 |
09:40:03.36 |
-19:42:49.8 |
HIP 47429 |
10.23 |
| 2026-02-10 00:00 |
09:40:00.48 |
-19:42:37.8 |
HIP 47429 |
9.82 |
| 2026-02-10 12:00 |
09:39:57.60 |
-19:42:25.7 |
HIP 47429 |
9.44 |
| 2026-02-11 00:00 |
09:39:54.71 |
-19:42:13.3 |
HIP 47429 |
9.10 |
| 2026-02-11 12:00 |
09:39:51.83 |
-19:42:00.7 |
HIP 47429 |
8.81 |
| 2026-02-12 00:00 |
09:39:48.95 |
-19:41:47.9 |
HIP 47429 |
8.55 |
| 2026-02-12 12:00 |
09:39:46.06 |
-19:41:34.8 |
HIP 47429 |
8.35 |
| 2026-02-13 00:00 |
09:39:43.18 |
-19:41:21.6 |
HIP 47429 |
8.20 |
| 2026-02-13 12:00 |
09:39:40.30 |
-19:41:08.2 |
HIP 47429 |
8.10 |
| 2026-02-14 00:00 |
09:39:37.41 |
-19:40:54.5 |
HIP 47429 |
8.07 |
| 2026-02-14 12:00 |
09:39:34.53 |
-19:40:40.7 |
HIP 47429 |
8.09 |
| 2026-02-15 00:00 |
09:39:31.65 |
-19:40:26.6 |
HIP 47429 |
8.18 |
| 2026-02-15 12:00 |
09:39:28.78 |
-19:40:12.3 |
HIP 47429 |
8.32 |
| 2026-02-16 00:00 |
09:39:25.90 |
-19:39:57.9 |
HIP 47429 |
8.52 |
| 2026-02-16 12:00 |
09:39:23.02 |
-19:39:43.2 |
HIP 47429 |
8.77 |
| 2026-02-17 00:00 |
09:39:20.15 |
-19:39:28.3 |
HIP 47429 |
9.07 |
| 2026-02-17 12:00 |
09:39:17.28 |
-19:39:13.2 |
HIP 47429 |
9.41 |
| 2026-02-18 00:00 |
09:39:14.42 |
-19:38:57.9 |
HIP 47429 |
9.79 |
| 2026-02-18 12:00 |
09:39:11.55 |
-19:38:42.5 |
HIP 47429 |
10.21 |
| 2026-02-19 00:00 |
09:39:08.69 |
-19:38:26.8 |
HIP 47429 |
10.65 |
| 2026-02-19 12:00 |
09:39:05.83 |
-19:38:10.9 |
HIP 47429 |
11.13 |
| 2026-02-20 00:00 |
09:39:02.98 |
-19:37:54.9 |
HIP 47429 |
11.62 |
| 2026-02-20 12:00 |
09:39:00.13 |
-19:37:38.6 |
HIP 47429 |
12.14 |
| 2026-02-21 00:00 |
09:38:57.29 |
-19:37:22.1 |
HIP 47429 |
12.67 |
| 2026-02-21 12:00 |
09:38:54.45 |
-19:37:05.5 |
HIP 47429 |
13.23 |
| 2026-02-22 00:00 |
09:38:51.61 |
-19:36:48.7 |
HIP 47429 |
13.79 |
| 2026-02-22 12:00 |
09:38:48.78 |
-19:36:31.7 |
HIP 47429 |
14.37 |
| 2026-02-23 00:00 |
09:38:45.95 |
-19:36:14.5 |
HIP 47429 |
14.96 |
| 2026-02-23 12:00 |
09:38:43.13 |
-19:35:57.1 |
HIP 47429 |
15.56 |
| 2026-02-24 00:00 |
09:38:40.32 |
-19:35:39.5 |
HIP 47429 |
16.16 |